Electrical control device for scale-model railroads



May 5, 1953 2,637,796

ELECTRICAL CONTROL DEVICE FOR SCALE-MODEL RAILROADS W. S. PIKE, JR

Filed Jan. 15, 1952 Patented May 5, 1953 UNITED STATES PATENT OFFICE ELECTRICAL CONTROL DEVICE FOR- SCALE-MODEL RAILROADS 4 Claims.

The invention relates to improvements in devices used, to control direct-current circuits in which it isnecessary to vary the resistance and reverse the polarity. The primarily intended, although not necessarily the sole, application for the invention is in speed and direction control of-scale-model railroad trains where direct current is used for propulsion and reversal in direction of travel is accomplished by reversing the track polarity at the control panel.

The objects of the invention are, first, to provide for simplified speed and direction control of a train on main-line or yard trackage through manipulation of a single control knob (rather than the customary two separate controls: conventional rheostat and double-pole double-throw toggle) second, to permit stopping and reversing the train without the necessity of running the rheostat to the extreme oft-end position (thus speedingup operations in yards, on grades, and when running heavy trains, and providing for emergency stops); and, third, to provide a separate non-reversing circuit for powering reversing loops of track (wherein, because a train leaving the main-line and entering the loop? travelling, say, west will reenter the main travelling east, it is necessary to reverse the polarity of the main-line without afiectingthe speed or directionof the train moving in the loop One form of the invention is illustrated in the accompanying drawing in which Figure 1 is a side elevation of the device; Figure 2, a vertical section on line 2-2, Figure 1; Figure 3, a top view of the center block showing the'arrange ment of the contacts; Figure 4, a vertical section drawn diagonally through the center assembly; Figure 5, a vertical diagonal view of the center assembly; Figure 6, a bottom view of the center block; and Figure 7, a top View of the rotor.

The frame of the device may be bolted in one piece or may be built up of separate pieces consisting of a slotted top, I, two end blocks, 2 and 3, and two side pieces, 4 and 5 (Figures 1 and 2).

Aflixed to the end blocks are two parallel fiat coils, 6 and l, of suitable total resistance. The coils are preferably taper wound to effect a better correspondence between the amount of movement of the control knob or lever and the change in speed of the train; tapering may be provided by (a) varying the size of the coil form as shown in the drawing (Figure 1) or (b) varying the size of the wire, or (c) varying the spac ing of the winding. The coils terminate at one end in terminals 8 and 9.

Mounted between the coils 6 and 1 is a movr tact points 253 and 21 (Figure 6).

able contact-bearing center assemblyof suitable non-conductive material which may be constructed as a slide, or as a lever as shown in the drawing. The center assembly contains a builtin double-pole double-throw center-off switch which is operated by rotation of the control knob and which may be, of the toggle type suitably mounted, or of the rotary type, or may consist of cam-actuated contacts. The drawing shows a simple rotary type in a center assembly suspended on pivot bolts l0 and Il from the side pieces 4 and 5; and consisting of a squar center block l2; a round rotor 53; rotor shaft I l; cap 15; and collar is, which holds the rotor and shaft in place. The control knob l? is mounted on the shaft I l.

The electrical contacts are arranged as follows: two spring contacts, l8 and I9, are mounted on opposite sides of the center block l2, extending downward to maize wiping contact with the coils 6 and l and extending upward to the top of the center block as shown in Figure 3. There they join wires, or rods extending downward through the center block and terminating in con- Two additional contact points, 22 and. 23, are connected through the'center block to contacts 24 and 25 mounted on the top of the block, which make wiping contact with strips terminating in terminals 26 and 21' (Figures land 2 Terminals 28 and 29 make, contact with spring contacts l9 and i3, respec tively, through pivots ii and Ill. Set into a recess in the rotor it are two spring contacts,3ll and 3!, as shown in Figure '7, so arranged that in one setting of the control knob, spring 30 makes contact between contact points 21 and 23, and spring tl, between points 2:? and 22. Rotation of the control knob (and rotor) through -degrees breaks both contacts (the center-oil position); a further rotation of 45-degrees establishes contact between points 2| and 22, and

between 20 and 23.

The edge of the rotor is shaped as shown in Figure '7, to engage a spring, 32, and provide stops at 45-degree rotation on both sides of the centerposition.

The circuits are as follows: the coil terminals 8 and 9 are the input terminals and are connected to the plus and minus terminals of the direct-current power source. The non-reversoircuit is completed between terminals 8 and 29 through coil 6, contact 18, and pivot l0; and between terminals 9 and 23 through coil 1, contact l9, and pivot l 1. In the reversing circuit, at one setting of the control knob, the circuit is completed between terminals 8 and 27 through coil 6, contact l8, point 20, contact 3|, point 23, and contact 25; and between terminals 9 and 26 through coil 1, contact [9, point 2|, contact 30, point 22, and contact 24. At the opposite setting of the knob (90-degree rotation) the circuit is completed between terminals 8 and 26 through coil 6, contact I8, point 20, contact 3|, point 22, and contact 24; and between terminals 9 and 21 through coil 1, contact l9, point 21, contact 30, point 23, and contact 25.

I am aware that prior to my invention reversing rheostats have been made, which require that the rheostat be run to the off-end before the circuit can be broken or its polarity reversed; and in which the movement of the lever or knob in one direction first increases the resistance, then breaks the circuit, and finally, with further movement in the same direction, decreases the resistance with the polarity of the circuit reversed. I therefore do not claim reversing rheostats broadly; but I claim:

I 1. A reversing rheostat which permits the circuit in which it is used to be broken and its polarity reversed without changing the resistance value, the device comprising a frame, appropriate electrical resistance suitably arranged and mounted on the said frame, a center as sembly pivotally mounted on the said frame and provided with a control lever and with contacts arranged so that movement of the assembly on its pivotal axis by means of the said control lever introduces continuously variable resistance into the circuit in which the device is used, the said control lever being mounted in the said center assembly for rotation about its longitudinal axis independently of the pivotal movement of the said assembly, an electrical switch of suitable design mounted on the said center assembly and attached to the said control lever in such a way as to be operated by rotation of the said control lever about its longitudinal axis, and contacts and terminals attached and arranged so that rotation of the said control lever about its longitudinal axis first breaks the said circuit and then re-establishes it but with reverse polarity.

2. The combination in a single device operated by a single control lever of a reversing rheostat and a non-reversing rheostat, the said device comprising the structure set forth in claim 1, and being provided with additional contacts and terminals arranged and attached in such a manner as to by-pass the said electrical switch and to provide a second output circuit which is unaffected by rotation of the said control lever about its longitudinal axis but in which the resistance value is always the same as that in the 4 first-mentioned circuit at any setting of the said control lever upon its pivotal axis.

3. A reversing rheostat which permits the circuit in which it is used to be broken and its polarity reversed Without changing the resistance value, the device comprising a frame, appropriate electrical resistance suitably arranged and mounted on the said frame, a center assembly mounted within the said frame for sliding movement parallel with the said electrical resistance, the said center assembly being provided with a control knob and with contacts arranged so that sliding movement of the said center assembly by means of the said control knob introduces continuously variable resistance into the circuit in which the device is used, the said control knob being mounted in the said center assembly for rotation about its longitudinal axis independently of the sliding movement of the said center assembly, an electrical switch of suitable design mounted on the said center assembly and attached to the said control knob in such a way as to be operated by rotation of the said control knob about its longitudinal axis, and contacts and terminals attached and arranged so that rotation of the said control knob about its longitudinal axis first breaks the said circuit and then re-establishes it but with reverse polarity.

4. The combination in a single device operated by a single control knob of a reversing rheostat and a non-reversing rheostat, the said device comprising the structure set forth in claim 3, and being provided with additional contacts and terminals arranged and attached in such a manner as to by-pass the said electrical switch and to provide a second output circuit which is un-,

affected by rotation of the said control knob about its longitudinal axis but in which the resistance value is always the same as that in the first-mentioned circuit at any setting of the said control knob in its slide.

WILLIAM SIBLE-Y PIKE, JR.

References Cited in the file of this patent UNITED STATES PATENTS Great Britain Oct. 30,1926 

